The CellCast Aggregator Gateway™ accepts messages from a virtually unlimited number and variety of message origination entities (including CAP 1.1 and CAP 1.2 sources), authenticates the message sender, authenticates the message, applies authorization rules, identifies the geo-targeted area to which the message is to be sent, applies CAP Protocols, reformats the message to CMAC where applicable (for CMSP Gateway delivery) and finally delivers the messages based on priority to wireless carriers in the geo-targeted area. The CellCast Aggregator Gateway™ acts a validation and clearing-house for point-to-multipoint communications technology, such as "cell broadcast", which can be used effectively for emergency alerts, notifications and commercial applications.